Flashback precluding torch

ABSTRACT

A flashback precluding torch is attachable to an aerosol propane canister containing propane gas under pressure and has a fixture receiving fitting. The flashback precluding torch comprises an elongate hollow main body member having an anchored end and a free end, a gas flow inlet disposed at the anchored end, a gas flow outlet disposed at the free end, and a gas flow passage connecting in fluid communication the inlet and the outlet. An attachment mechanism is provided for removably attaching the anchored end of the elongate hollow main body member to the fixture receiving means of the aerosol propane canister. A manually operable main valve is operatively mounted on the elongate hollow main body member. A flame directing nozzle is operatively mounted on the main body member at the free end. A safety flow valve is operatively mounted on the elongate hollow main body member, so as to control the flow of propane through the elongate hollow main body member.

FIELD OF THE INVENTION

[0001] The present invention relates to portable propane torches and portable propane burners and more particularly to safety valves for such portable propane torches and portable propane burners.

BACKGROUND OF THE INVENTION

[0002] It is well known to provide portable propane torches for use in welding pipes and so on, and also for other uses. It is also well known to provide portable propane burners for use in outdoor cooking and heating. Typically, these portable propane torches and portable propane burners obtain their fuel from small refillable containers filled with pressurized propane. Commonly, these containers are made from cold rolled steel and are quite cumbersome and heavy, and are also reasonably expense compared to the amount of propane they contain. More recently, smaller aerosol types of containers containing propane have been made available, as disclosed, for instance, in U.S. Pat. No. 5,285,916 issued Feb. 15, 1994 to Ross.

[0003] In use, portable propane torches and portable propane burners are susceptible to flashback, among other problems. Flashback occurs when the flow of propane is not steady and continuous. An unsteady, a discontinuous, or an abruptly surging flow of propane might occur when the propane cylinder is moved quickly, is oriented at a downwardly facing angle, is running low on propane, or for a variety of other reasons. In any event, the resulting flame from the unsteady, or discontinuous, or abruptly surging flow of propane can be quite dangerous, or at least can be an annoyance, especially when working with a propane torch trying to produce a fine weld seam.

[0004] In order to solve the problem of flashback, the larger cold rolled steel refillable propane tanks have a safety flow valve disposed at the “bottom end” of the burner attachment, or in other words, where the burner attachment threadibly engages onto the portable propane tank. This safety flow valve helps preclude flashback in the event that the propane tank is knocked over, oriented upside down for a considerable period of time, moved around significantly, and so on.

[0005] However, in the portable aerosol propane canister, there is no room between the attachment and the aerosol propane tank to place a valve. There is also no other location in the torch attachment where it is apparent that a valve can be placed.

[0006] Accordingly, there is no known portable torch powered by an aerosol propane canister, that has a safety flow valve incorporated therein, which is highly undesirable and even quite dangerous. Also, there is no known safety flow valve usable in a portable torch powered by an aerosol propane canister.

[0007] Further, there is no known portable burner powered by an aerosol propane canister, that has a safety flow valve incorporated therein, which is highly undesirable and even quite dangerous. Also, there is no known safety flow valve usable in a portable burner powered by an aerosol propane canister.

[0008] It is an object of the present invention to provide a portable torch powered by an aerosol propane canister, wherein the portable torch has a safety flow valve incorporated therein.

[0009] It is an object of the present invention to provide a safety flow valve usable in a portable torch powered by an aerosol propane canister.

[0010] It is another object of the present invention to provide a portable burner powered by an aerosol propane canister, wherein the portable burner has a safety flow valve incorporated therein.

[0011] It is yet another object of the present invention to provide a safety flow valve usable in a portable burner powered by an aerosol propane canister.

SUMMARY OF THE INVENTION

[0012] In accordance with one aspect of the present invention there is disclosed a flashback precluding torch attachable to an aerosol propane canister containing propane gas under pressure and having a fixture receiving means. The flashback precluding torch comprises an elongate hollow main body member having an anchored end and a free end, a gas flow inlet disposed at the anchored end, a gas flow outlet disposed at the free end, and a gas flow passage connecting in fluid communication the inlet and the outlet. An attachment means is provided for removably attaching the anchored end of the elongate hollow main body member to the fixture receiving means of the aerosol propane canister. A manually operable main valve is operatively mounted on the elongate hollow main body member. A flame directing nozzle is operatively mounted on the main body member at the free end. A safety flow valve is operatively mounted on the elongate hollow main body member, so as to control the flow of propane through the elongate hollow main body member.

[0013] Other advantages, features and characteristics of the flashback precluding torch according to the present invention, will become more apparent upon consideration of the following detailed description and the appended claims with reference to the accompanying drawings, the latter of which is briefly described herein below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The novel features which are believed to be characteristic of the flashback precluding torch according to the present invention, as to its structure, function, use and method of operation, together with further objectives and advantages thereof, will be better understood from the following drawings in which a presently preferred embodiment of the invention will now be illustrated by way of example. It is expressly understood, however, that the drawings are for the purpose of illustration and description only, and are not intended as a definition of the limits of the invention. In the accompanying drawings:

[0015]FIG. 1 is an exploded perspective view of the preferred embodiment of the flashback precluding torch of FIG. 1;

[0016]FIG. 2 is a side elevational view of the preferred embodiment of the flashback precluding torch of FIG. 1;

[0017]FIG. 3 is a side elevational view of the safety flow valve of the preferred embodiment of the flashback precluding torch of FIG. 1;

[0018]FIG. 4 is an end elevational view of the safety flow valve of FIG. 3;

[0019]FIG. 5 is a cross-sectional side elevational view of the safety flow valve of FIG. 4, in an open configuration; and,

[0020]FIG. 6 is a cross-sectional side elevational view of the safety flow valve of FIG. 4, in an open configuration.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

[0021] Reference will now be made to FIGS. 1 through 6, which show a preferred embodiment of the flashback precluding torch 20 according to the present invention. The preferred embodiment flashback precluding torch 20 is attachable to an aerosol propane canister 22 containing propane gas under pressure and having a fixture receiving means, namely a threaded post 24.

[0022] The flashback precluding torch 20 comprises an elongate hollow main body member 30 which preferably comprises a cylindrical brass tube. The elongate hollow main body member 30 has an anchored end 32 and a free end 34. A gas flow inlet 36 is disposed at the anchored end 32 of the elongate hollow main body member 30 so as to be in position to receive propane gas from the aerosol propane canister 22 when the flashback precluding torch 20 is mounted onto the flashback precluding torch 20. A gas flow outlet 38 is disposed at the free end 34 of the elongate hollow main body member 30. A gas flow passage 39 connects in fluid communication the gas flow inlet 36 and the gas flow outlet 38.

[0023] An attachment means 40 for removably attaching the anchored end 32 of the elongate hollow main body member 30 to the fixture receiving means, namely the threaded post 24, of the aerosol propane canister 22 comprises a fitting 40 having a threaded female portion 42 that co-operatingly engages the threaded post 24 of the aerosol propane canister 22.

[0024] A manually operable main valve 50 is operatively mounted on the elongate hollow main body member 30. In the preferred embodiment illustrated, the manually operable main valve 50 is mounted on the attachment means 40, and has a knurled flow control knob 52 press fit onto a post 54 that is threadibly engaged within the fitting 40.

[0025] A flame directing nozzle 60 is operatively mounted on the elongate hollow main body member 30 at the free end 34, and is preferably threadibly engaged thereon for manufacturing purposes and to permit interchangeability.

[0026] A safety flow valve 70 is operatively mounted on the elongate hollow main body member 30, so as to control the flow of propane through the elongate hollow main body member 30. In the preferred embodiment illustrated, the safety flow valve 70 is operatively mounted on the elongate hollow main body member 30 between the manually operable main valve 50 and the flame directing nozzle 60, and specifically within the gas flow passage 39 of the elongate hollow main body member 30.

[0027] As can be best seen in FIGS. 3 and 4, the safety flow valve 70 is substantially cylindrically shaped and comprises an main body 72 having an inlet end 74 and an outlet end 76. A throughpassage 78 extends between the inlet end 74 and the outlet end 76, as can be best seen in FIGS. 5 and 6.

[0028] Further, the main body 72 is shaped to have an elongate narrow portion 80 along most of its length, a chamfer 81 adjacent the outlet end 76 and an annular flange 82 disposed adjacent the inlet end 74. The elongate narrow portion 80 is dimensioned to fit snugly within the gas flow passage 39 of the elongate hollow main body member 30. For ease of manufacture, the safety flow valve 70 is mounted into the elongate hollow main body member 30 by means of press fitting, as limited by the annular flange 82.

[0029] The safety flow valve 70 also comprises and end cap 84 press-fit into the throughpassage 78. A sliding stem valve 86 has a rubber “O”-ring 87 mounted on the stem portion 88 immediately below the head portion 89. The stem portion 88 is slidably mounted within a bore hole 90 disposed in the end cap 84, for movement between a gas flow permitting position, as is best shown in FIG. 5, and a gas flow precluding position, as is best shown in FIG. 6. The gas flow permitting position of the sliding stem valve 86 corresponds to the open configuration of the safety flow valve 70. Gas flow is generally shown by arrows “A” in FIG. 5. The gas flow precluding position of the sliding stem valve 86 corresponds to the closed configuration of the safety flow valve 70.

[0030] A end insert 91 having a bore hole 93 is retained in press-fit relation within the throughpassage 78 at the outet end 76 of the main body 72. An interior insert 92 having a bore hole 94 is slidably retained within the throughpassage 78 and is biased away from the end insert 91 by means of a coil spring 96.

[0031] Preferably, all of the major components of the flashback precluding torch 20, namely the elongate hollow main body member 30, the fitting, the manually operable main valve 50, the flame directing nozzle, and the safety flow valve 70 are all made from brass, for the purpose of cost effective manufacturing, and safety.

[0032] In use, when the propane is flowing continuously an at a substantially constant flow rate from the aerosol propane canister 22 and through the flashback precluding torch 20, propane flows through the bore holes 92,94 of the first insert 91 and second insert 92, respectively. The gas flow emanating from the bore hole 94 of the second insert 92 moves the sliding stem valve 86 to its gas flow permitting position, as shown in FIG. 5. During a potential flashback, the gas flow is not continuous, and the coil spring 96 biases the second insert 92 against the head portion 89 of the sliding stem valve 86, thus closing off the bore hole 94 and precluding the combustion of the gas from travelling back into the aerosol propane canister 22, thereby precluding flashback.

[0033] As can be understood from the above description and from the accompanying drawings, the present invention provides a flashback precluding torch powered by an aerosol propane canister, which flashback precluding torch has a safety flow valve incorporated therein, all of which features are unknown in the prior art.

[0034] Other variations of the above principles will be apparent to those who are knowledgeable in the field of the invention, and such variations are considered to be within the scope of the present invention. Further, other modifications and alterations may be used in the method of providing flashback precluding torch of the present invention without departing from the spirit and scope of the accompanying claims. 

I claim:
 1. A flashback precluding torch attachable to an aerosol propane canister containing propane gas under pressure and having a fixture receiving means, said flashback precluding torch comprising: an elongate hollow main body member having an anchored end and a free end, a gas flow inlet disposed at said anchored end, a gas flow outlet disposed at said free end, and a gas flow passage connecting in fluid communication said inlet and said outlet; attachment means for removably attaching said anchored end of said elongate hollow main body member to said fixture receiving means of said aerosol propane canister; a manually operable main valve operatively mounted on said elongate hollow main body member; a flame directing nozzle operatively mounted on said main body member at said free end; and, a safety flow valve operatively mounted on said elongate hollow main body member, so as to control the flow of propane through the elongate hollow main body member.
 2. The flashback precluding torch as set forth in claim 1, wherein said safety flow valve is operatively mounted on said elongate hollow main body member between said manually operable main valve and said flame directing nozzle.
 3. The flashback precluding torch as set forth in claim 2, wherein said safety flow valve is mounted within said gas flow passage of said elongate hollow main body member.
 4. The flashback precluding torch as set forth in claim 3, wherein said elongate hollow main body member comprises a cylindrical tube.
 5. The flashback precluding torch as set forth in claim 1, wherein said safety flow valve is substantially cylindrically shaped.
 6. The flashback precluding torch as set forth in claim 5, wherein said safety flow valve is mounted into said gas flow passage of said elongate hollow main body member by means of press fitting.
 7. The flashback precluding torch as set forth in claim 6, wherein said substantially cylindrically shaped safety flow valve comprises an elongate narrow main body and an annular flange disposed adjacent one end of said elongate narrow main body.
 8. The flashback precluding torch as set forth in claim 1, wherein said manually operable main valve is mounted on said attachment means. 